CVE-2025-21853

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Source
https://cve.org/CVERecord?id=CVE-2025-21853
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-21853.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2025-21853
Downstream
Related
Published
2025-03-12T09:42:07.871Z
Modified
2026-03-20T12:41:12.812602Z
Summary
bpf: avoid holding freeze_mutex during mmap operation
Details

In the Linux kernel, the following vulnerability has been resolved:

bpf: avoid holding freeze_mutex during mmap operation

We use map->freezemutex to prevent races between mapfreeze() and memory mapping BPF map contents with writable permissions. The way we naively do this means we'll hold freeze_mutex for entire duration of all the mm and VMA manipulations, which is completely unnecessary. This can potentially also lead to deadlocks, as reported by syzbot in [0].

So, instead, hold freeze_mutex only during writeability checks, bump (proactively) "write active" count for the map, unlock the mutex and proceed with mmap logic. And only if something went wrong during mmap logic, then undo that "write active" counter increment.

[0] https://lore.kernel.org/bpf/678dcbc9.050a0220.303755.0066.GAE@google.com/

Database specific 
{
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21853.json"
}
References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
fc9702273e2edb90400a34b3be76f7b08fa3344b
Fixed
2ce31c97c219b4fe797749f950274f246eb88c49
Fixed
0d90d9e154144a3a80e9fc0eb9b21b7fc990f68f
Fixed
4759acbd44d24a69b7b14848012ec4201d6c5501
Fixed
29cfda62ab4d92ab94123813db49ab76c1e61b29
Fixed
d95607a5f2f9bb08194c9deaf4a5f3e8ba59a9d4
Fixed
271e49f8a58edba65bc2b1250a0abaa98c4bfdbe
Fixed
bc27c52eea189e8f7492d40739b7746d67b65beb

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-21853.json"